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When to plant Sunflower in Rawlins County, KS

Rawlins County's climate puts the Sunflower spring window between May 8 and May 29. time plantings around the expected last-frost window for best survival.

When to Plant Sunflower in Rawlins County, KS

Rawlins County, Kansas Zone 6a June

Your June planting checklist for Rawlins County, Kansas

Each item below is timed to Rawlins County, Kansas's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 1
Avg. first frost October 10
Soil temp (4") 68°F
Watering High
Pest pressure High
Daylight 14.8 hrs
Coming up in July — start thinking about
  • First harvests: sunflower

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Sunflower (Helianthus annuus) is a fast-growing North American native annual famous for its towering stems and brilliant yellow heads. It thrives in full sun and heat, producing large, pollen-rich blooms that attract bees, butterflies, and seed-eating birds. Varieties range from 18-inch dwarfs to 12-foot giants and nearly every color except blue.

Rawlins County, Kansas is in USDA Zone 6a. The average last spring frost is May 1 and the first fall frost is October 10, giving you a growing season of approximately 162 days.

At an elevation of 795 feet, Rawlins County receives approximately 34.1 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Sunflower during the growing season.

Annual Blooms in Summer Pollinator-friendly Good for cutting
Rawlins County, KS (Zone 6a) Moderate season
162 days
Last Spring Frost May 1
162 growing days
First Fall Frost October 10

Rawlins County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.8

Drainage

Well Drained

Sunflower Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 4 Transplant: May 2 🌸 Bloom: Jul 25 – Oct 17
Recommended (50%) ✗ May not fit
Start indoors: Apr 10 Transplant: May 8 🌸 Bloom: Jul 31 – Oct 23
Safe Start (90%) ✗ May not fit
Start indoors: Apr 22 Transplant: May 20 🌸 Bloom: Aug 12 – Nov 4

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Soil Compatibility in Rawlins County

How your county's soil matches Sunflower's growing requirements.

Soil pH

Your soil pH (6.7–7.8) overlaps with Sunflower's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Rawlins County is excellent for Sunflower — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.6%). Annual compost additions will help Sunflower.

How to Plant Sunflower

1"
Planting Depth
18"
Between Plants
24"
Between Rows

Succession Planting Sunflower

2
successive plantings in your 162-day season

Sow every 8 weeks. Last sowing by Jul 02 to harvest before frost.

Sunflower Water Budget

Plant needs
0.5″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Sunflower

Sunflower needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Sunflower Needs Rainfall You Supplement Action
Jan 2.6" 0" ❄️ Dormant
Feb 2.2" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 3.5" 0" ❄️ Dormant
May 2.2" 4.3" 0" ✅ Rainfall sufficient
Jun 2.2" 2" 0.2" 💧 Light watering
Jul 2.2" 3.1" 0" ✅ Rainfall sufficient
Aug 2.2" 4" 0" ✅ Rainfall sufficient
Sep 2.2" 2.6" 0" ✅ Rainfall sufficient
Oct 2.2" 3.1" 0" ✅ Rainfall sufficient
Nov 2.1" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Rawlins County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Sunflower Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Sunflower needs ~1,296 GDD — county provides 2,470 GDD Excellent fit

Sunflower Planting Timeline — Rawlins County, KS

Sunflower Planting Calendar

Activity When Date Range
Start Indoors April 10 Apr 10 – Apr 24
Transplant Outdoors May 8 May 8 – May 22
Direct Sow May 8 May 8 – May 29
Bloom July 31 Jul 31 – Oct 23

Plant 1" deep · 18" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Transplant Outdoors Direct Sow
June
July Bloom
August Bloom
September Bloom
October Bloom
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 6a

📆 Growing Season

162 days in Rawlins County

Growing Tips for Sunflower in Rawlins County

Direct sow Sunflower outdoors after May 01 in Rawlins County when soil has warmed and frost danger has passed.

Common pests for Sunflower in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct-sow 1 inch deep after last frost; germination takes 7-14 days at 65-75°F soil. Sunflowers dislike root disturbance so direct sowing is strongly preferred over transplanting. Plant in succession every 2 weeks for extended bloom. Stake tall varieties. Avoid overwatering — they tolerate drought once established. Birds will self-deadhead seed heads; leave them up through fall for wildlife.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes
  • Pole_beans

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sunflower in Rawlins County, KS?

Rawlins County is in Zone 6a with an average last frost of May 1. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Rawlins County, KS?

Rawlins County, Kansas is in USDA Hardiness Zone 6a. The average last spring frost is May 1 and first fall frost is October 10.

When should I plant Sunflower in Rawlins County, KS?

In Rawlins County, KS, plant Sunflower after the last frost (around May 1) and before the first frost (around October 10). Best results when soil holds above 50°F.

What growing zone is Rawlins County, KS for Sunflower?

Rawlins County sits in USDA Zone 6a. Sunflower grows reliably in zones 2a through 11b, so it's a good fit here.

Can Sunflower grow in Rawlins County's climate?

Yes — Sunflower grows well in Rawlins County's temperate climate. Rawlins County averages a 162-day frost-free season, with last frost around May 1 and first frost around October 10.

🌱

Your Rawlins County Garden Planner — Free

A 22-page printable planner built for Rawlins County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Rawlins County, KS. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.